Accelerator column

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
George Schmermund
Posts: 262
Joined: Wed Aug 16, 2006 12:51 am
Real name: George Schmermund
Location: Carlsbad, CA

Re: Accelerator column

Post by George Schmermund » Sun Jan 10, 2010 8:25 pm

Steve - Sounds good to me. I'd have done the same thing if I wasn't so lazy. Once again, I was only testing the parts and method of assembly.
Anything obvious in high vacuum is probably wrong.

Dustinit
Posts: 257
Joined: Wed Mar 19, 2008 12:02 am
Real name:

Re: Accelerator column

Post by Dustinit » Mon Jan 11, 2010 12:41 am

I like this.
Looks like it could be directly coupled to the stages of a cw multiplier too.
RF acceleration might also be possible by extending each coupling a bit towards the source although the freq would probably be too high with such short stages.
Dustin

ggombert
Posts: 17
Joined: Sun Apr 04, 2004 6:15 pm
Real name:

Re: Accelerator column

Post by ggombert » Thu Feb 24, 2011 8:01 pm

Hi,
I was wondering if anyone had done anything more with the concept that George came up with for a low cost accelerator column since this thread was originally posted?

Questions that come to mind are:

-- The first stage would probably need a variable resistor to focus the beam; the rest of the elements could use fixed resistors (perhaps the 200 M ohm) that is mentioned in the original description.
-- Would the proposed assembly method allow 10-5 vacuum without any additional sealing (or would something like this be required)?
-- Would simple corona barrier be a smaller hole in the ½ inch coupling made with a piece of copper/brass and attached before the sections are assembled?
-- Of the many good ion sources described in the forum what would be the simplest to use with this sort of accelerator column?

This seems like too neat a simple concept not to at least try and carry the design a bit further to a working prototype.

Cheers,
Glenn

John Futter
Posts: 1455
Joined: Thu Apr 22, 2004 2:29 am
Real name: John Futter
Contact:

Re: Accelerator column

Post by John Futter » Thu Feb 24, 2011 10:48 pm

Glen
Good questions
The simplest ion sources would be either Carl Willis;s HFRF driven one or Doug Coulters Microwave oven derived source. other possiblities include cold cathode penning type.

1x 10 e -5 Millibar should be very easy to get with what George has presented. Bear in mind that you would want to operate the tube an order of magnitude below this for best results (beam spreading due to neutrals).

A 50 l/s turbo would be heaps for this

and yes the top tube section is generally referred to as the Focus electrode

ggombert
Posts: 17
Joined: Sun Apr 04, 2004 6:15 pm
Real name:

Re: Accelerator column

Post by ggombert » Mon Feb 28, 2011 5:39 pm

Hi,
The attached file describes a simple ion source that is similar to what was used on the original Amateur Scientist article in 1971. It was built by a group of students that modeled what they built loosely based on that article. Would this type of design be suitable for use with the accelerator column discussed here or is something more sophisticated required?
Thanks,
Glenn
Attachments
Ion Source.doc
(98.5 KiB) Downloaded 205 times

John Futter
Posts: 1455
Joined: Thu Apr 22, 2004 2:29 am
Real name: John Futter
Contact:

Re: Accelerator column

Post by John Futter » Mon Feb 28, 2011 6:48 pm

Glenn
Yes will work albeit badly
if a permanent magnet was put around the glass tube then you have a cold cathode penning type which will produce around 100x as many ions as what you presented
Reading all of this especially the chapters on ion sources should put things in perspective
viewtopic.php?f=6&t=3115#p12625

Post Reply